Optical Scanning Device Single Expander Lens Path Alignment
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Solution Overview
Problem
In optical scanning devices, the close arrangement of laser diodes in the height direction to optimize optical performance results in shifted positions and differing optical paths, necessitating multiple return mirrors and lenses, which increases complexity and cost.
Innovation Solution
The optical scanning device aligns the optical path lengths from multiple light sources to a rotary polygon mirror by using a single first expander lens, ensuring overlapping optical paths in the main scanning direction, and optionally incorporating a cylindrical lens and a second expander lens to manage beam expansion and collimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple laser diodes are arranged close together in the height direction to optimize optical performance, then beam size and optical performance are improved, but the positions of the laser diodes are shifted with respect to the main scanning direction, causing differing optical paths that require multiple return mirrors and lenses, increasing device complexity
Solution Approach 1:
The patent merges the optical paths of multiple laser diodes by arranging them linearly in the sub-scanning direction so that their beams overlap in the main scanning direction. This allows multiple optical paths to be combined into a single unified path, eliminating the need for multiple separate return mirrors and lenses, thus reducing device complexity while maintaining optimized beam characteristics
Solution Approach 2:
The patent transitions the arrangement of laser diodes from the height direction (vertical stacking) to the sub-scanning direction (horizontal linear arrangement). This dimensional change allows the beams to overlap in the main scanning direction without requiring multiple return mirrors, as the linear arrangement in the sub-scanning direction naturally aligns the optical paths
2Illumination intensity
If multiple laser diodes are arranged obliquely side by side to optimize optical performance, then beam characteristics are improved, but multiple return mirrors and lenses are required to compensate for shifted positions, increasing manufacturing cost
Solution Approach 1:
The patent combines multiple optical paths into a single path by arranging laser diodes linearly in the sub-scanning direction. This merging eliminates the need for multiple separate optical components (return mirrors and lenses), thereby reducing the number of parts that need to be manufactured and assembled, which directly reduces manufacturing cost
Solution Approach 2:
The patent extracts the unnecessary optical components (multiple return mirrors and lenses) from the system by redesigning the laser diode arrangement. By removing these extra components, the manufacturing process is simplified, and material costs are reduced
3Manufacturing precision
If multiple return mirrors and lenses are used to compensate for shifted laser diode positions, then optical path alignment is achieved, but the device size increases and space efficiency is reduced
Solution Approach 1:
The patent merges multiple optical paths into a single overlapping path arrangement, which eliminates the need for multiple return mirrors and lenses. This consolidation significantly reduces the space required for optical components and their mounting, thereby reducing overall device size while maintaining proper optical path alignment
Solution Approach 2:
By changing the arrangement from vertical stacking to horizontal linear arrangement in the sub-scanning direction, the patent enables optical paths to overlap in the main scanning direction. This dimensional reorganization allows for more compact device design with reduced volume
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for equal optical path lengths and aligned focal points, simplifying the device design, reducing costs, and facilitating space-saving solutions while maintaining effective optical performance.
Implementation Method 1
a first expander lens that expands the beams emitted from the plurality of light sources in a main scanning direction
Implementation Method 2
a cylindrical lens that changes an incident angle with respect to the rotary polygon mirror in a sub-scanning direction orthogonal to the main scanning direction
Data Source
AI summary
An optical scanning device includes a first expander lens that expands beams emitted from a plurality of laser diodes in a main scanning direction. The beams emitted from the plurality of laser diodes are incident on the first expander lens, the first expander lens being a single lens. The plurality of laser diodes are disposed with optical paths of the beams from the plurality of light sources to a polygon mirror (rotary polygon mirror) overlapping each other in the main scanning direction when viewed from a direction along a rotary shaft of the polygon mirror.